ELECTRONIC APPARATUS USING INFORMATION MEMORY MEDIUM

Abstract: There is provided an electronic appliance such as a gam machine which takes less time to read visually recognizable information from a CD-ROM and improves the level of security to eliminate further effectively imitation. The apparatus includes a CD-ROM drive for a CD-ROM (12) having visually recognizable display information, an information detection portion (18) for detecting specific information selected from unit information constituting compared data (A), and a comparator portion (19) having original check data (D) corresponding to the compared data (A), for comparing the specific information with reference information corresponding to the specific information of the original check data (D) and outputting the result of comparison.

Description: TECHNICAL FIELD The present invention relates to an electronic device for reading information stored in an information storage medium, particularly an information processing device for optically reading program information stored in a CD-ROM to play a game. BACKGROUND ART Information from musical CDs and data CD-ROMs can be read by CD drives as long as they meet standards even if the CDs are counterfeits. This does not deter counterfeit manufacturers. As a countermeasure to this, various security systems have been proposed for the prevention of unauthorized copying of games software, which have been developed as a result of a large investment of manpower and time. One such security system is disclosed in EP-A-0545472, which particularly aims to prevent the unauthorized copying of a record carrier such as a CD. Information is stored on the carrier in the form of variations in a first physical parameter such as the lengths of pits along the track of the CD. A security signal is stored in the form of variations in a second physical parameter detectable by the same detector as the first physical parameter. For example, the second parameter may be the lateral displacement of the CD track, the width of the pits or the height of the disk surface. Copying systems generally record only the variations in the first parameter, which store the information, so unauthorized copies without variation in the second parameter may be rejected. A new security system for CD-ROMs is proposed in Japanese Patent Application No. Hei 05-185740/1993 and European Patent Application EP-A-0671730, which claims priority from that Japanese Application. Those Applications were filed by the present applicant before the filing date of the present Application but were not published until after that date. The disclosed security system detects whether or not specific indications, such as trademarks or others, are indicated at predetermined parts of CD-ROM discs, whereby the discs are judged to be genuine products or counterfeits. In the security system proposed in the above-described applications, when a specific indication is read, the entire specific indication is read, which unavoidably requires a certain reading time. Especially in a case that a specific indication is visibly displayed on an information storage surface using a group of pits over a plurality of tracks, all said tracks have to be read, which takes much reading time. Patent Application GB-A-2250626 discloses various ways of forming a visible indication on the surface of a CD over a plurality of tracks. The visible indication may arise from areas in which the tracks are broadened or narrowed, laterally displaced or divided into discrete pits. There is no suggestion that this system could be used in a security check of the disk. One object of the present invention is to provide an electronic device with a new security system built in, which can effectively reject or exclude counterfeit products. Another object of the present invention is to provide an electronic device and an information processing method which can reduce the reading time of a specific security indication. Another object of the present invention is to provide an electronic device and an information processing method which make it more difficult for counterfeiters to breach security systems. Another object of the present invention is to provide an electronic device and an information processing method which can effectively exclude counterfeit information storage media from the market even when security systems are breached. Still another object of the present invention is to provide an information processing method which can effectively reject or exclude the use of counterfeit information storage media. DISCLOSURE OF INVENTION The electronic device according to one embodiment of the present invention comprises a medium mounting unit on which an information storage medium is to be detachably mounted, and authenticity checking means for checking authenticity of the information storage medium; CHARACTERIZED IN THAT: the information storage medium comprises an information region, and an indication region on which a visual indication is formed so that the visual indication has a property of being visually recognizable by the human naked eye as well as a property of allowing the electronic device to read data necessary for the authenticity check when the electronic device detects a selected partial area of the indication region; and the authenticity checking means of the electronic device has a storage means which stores reference data indicative of the visual indication, selection means for selecting a partial area of the indication region, the selected partial area being less than the whole area of the indication region, detection means for detecting the selected partial area to output data indicative of part of the visual indication, and comparison means for comparing the detected data with the reference data. According to this embodiment, all of the information of an indication for the security check is not required to be detected. Instead, information from a selected part of the indication is detected, whereby a reading time of the indication information can be short. The electronic device according to another embodiment of the present invention is characterized in that the selection means selects at random the selected partial area of the selected track or tracks. According to this embodiment, the specific part to be selected from unit information constituting the indication information is changed at random for every read-out, so that when a counterfeiter makes an information storage medium compatible with the electronic device of the present invention, he has to illegally use the same indication information as that carried by an authentic information storage medium. Counterfeits can thus be more effectively excluded. The electronic device according to an alternative embodiment of the present invention comprises a means on which an information storage disc is to be mounted, and authenticity checking means for checking authenticity of the disc; CHARACTERIZED IN THAT: the disc comprises an information storing zone with information recorded with pits, and an indication forming zone defined in an area different from the information storing zone, the indication forming zone including a plurality of indication regions defined in the indication forming zone, each of said plurality of indication regions being formed with a visual indication so that the visual indication has a property of being visually recognizable by the human naked eye as well as a property of allowing the electronic device to read data necessary for the authenticity check; and the authenticity checking means of the electronic device has a storage means which stores reference data indicative of the visual indication, selection means for selecting a region at random from said plurality of indication regions, detection means for detecting the selected region to output data indicative of the visual indication, and comparison means for comparing the detected data with the reference data to check the authenticity of the disc. According to this embodiment, a plurality of indication regions of a disc are detected for the security check, so that security is further ensured. In addition, a required detection time is shortened because it is not necessary to detect all of the plural indication regions but to detect only a specific indication region selected at random. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of a game machine incorporating a security check system according to the present invention. FIG. 2 is a block diagram of the game machine incorporating the security check system according to the present invention. FIG. 3 is a plan view of a CD-ROM to which the security check system according to the present invention is applied. FIG. 4 is a view of one example of indications on the CD-ROM to be security checked. FIG. 5 is a partial sectional view of the CD-ROM to which the security check according to the present invention is applied. FIGs. 6A - 6C are views detailing formation of an indication to which the security check according to the present invention is applied. FIG. 7 is a block diagram of a reading unit for executing the security check according to the present invention. FIG. 8 is a view explaining original data for checking as a reference for comparison. FIG. 9 is a flow chart of the operation of the reading unit for the security check according to the present invention. FIGs. 10A - 10D are plan views of other examples of CD-ROMs to which the security check according to the present invention may be applied. BEST MODE FOR CARRYING OUT THE INVENTION A game machine including the electronic device according to one embodiment of the present invention will be explained with reference to the drawings. As shown in FIGs. 1 and 2, a game machine 10 includes a control unit 10a and a CD-ROM control unit 10b. The control unit 10a includes a game control unit 21 for controlling a game, an output interface 22 for supplying audio signals and video signals, input interfaces 23a, 23b for receiving operational signals, and input/output interfaces 24a, 24b for receiving/supplying a game program and data. The output interface 22, the input interfaces 23a, 23b and the input/output interfaces 24a, 24b are connected to the game control unit 21. As shown in FIG. 2, the control unit 10a is connected to a television unit 25 as a display unit for displaying contents of a game, and to various controllers, e.g. joy pads 26a, 26b, for manipulating the operation of the game through the input interfaces 23a, 23b. Thus the game machine comprises the game machine body 10, the television unit 25, the joy pads, etc. The numeral 10 refers herein to the main body of the game machine. The numeral 10 sometimes may refer in general to a game machine to which peripherals such as a joy stick are connected. The game machine 10 receives a game cartridge 28 in a cartridge receiver 29 of the control unit 10a and can conduct a game in accordance with a game program stored in a semiconductor ROM or RAM of the game cartridge 28. The game program stored in the semiconductor ROM or RAM is transmitted to the game control unit 21 through the input/output interface 24a. The CD-ROM control unit 10b includes a CD-ROM mount or drive unit 11 and an optical pickup 16. A CD-ROM 12 is mounted on the CD-ROM mount 11, so that program information stored in the CD-ROM 12 is detected by the optical pickup 16. When the program information recorded in the CD-ROM 12 is a game program, the read game program information is supplied to the game control unit 21 through the input/output interface 24b and the game is ready to be operated. The game cartridge 28 and the CD-ROM 12 function as information storing media, and the cartridge port or receiver 29 and the CD-ROM mount unit 11 function as a medium ports. The CD-ROM 12 is formed in a disc of thin transparent plastic as shown in FIG. 3 and has a center hole 12a formed in the center of the disc. The plastic substrate 13 of the CD-ROM 12 has a program region 14 with game program information recorded with pits between a read-in region 14a and a read-out region 14b. The program region 14 which is an information recording region has a trademark indication region 15 defined in a rectangular area over 100 - 200 tracks adjacent to the read-in region 14a without game program information recorded. In this specification, the region 15 may be referred to as "trademark indication region", "indication region" or "predetermined region/part". In the trademark indication region 15 data A which is a specific indication to be compared (see FIG. 4) is provided. The data A to be compared is formed with a set of pits and is recognized as pit array information when read by the optical pickup 16 provided in the CD-ROM control unit 10b. The data A to be compared is indication information stored in the trademark indication region 15 which is visually recognizable, and can be, in addition to a trademark, a mark, logotype, pattern, character or others. As shown in FIG. 5, the CD-ROM 12 stores image information in the form of a set of pits together with game program information in the form of a group of pits 35 in the upper side of the disc substrate 31 of transparent plastic, such as polycarbonate, acryl, vinyl polychloride or others. The upper side 33 in which the pits 35 are formed is covered with a reflecting layer 36, which is a metal layer of e.g. aluminium, and is covered further with a protection layer 37, whereby an outer surface 38 is formed. The protection layer 37 is usually formed of an opaque material, and a title, a design, an author of game software and a trademark etc. designated by a licensor if the production of the game software is licensed by a third party can be indicated on the outer surface 38. The information stored in the CD-ROM 12 is read by causing a laser beam to enter into the disc substrate 31 from the underside surface 34 thereof and reflect at the reflection layer 36 to be detected by the optical pickup 16 disposed facing the underside surface 34. A set of pits in the trademark indication region 15 is formed to be recognizable as a required shape visually from the underside surface 34, which is an optical detecting surface. A method for forming data A to be compared using pits will be explained with reference to FIGs. 6A to 6C. Data A to be compared, e.g. "SEGA" is formed in a set of pits as shown in FIG. 6A. The data A to be compared is visible (visually recognizable as a mark "SEGA") from the underside surface 34, the optical detecting surface, of the disc substrate 31, as shown in FIG. 5. Each dot making up the letters "SEGA" comprises a set of pit arrays enclosed by the broken line A in FIG. 6B, and the part with no letters comprises a set of pit arrays C in FIG. 6B. For example, a region enclosed by the broken line A is formed in one visible dot by longitudinally 70 tracks and transversely 12 pit arrays. For example, the pit arrays B provide a unit in which the area covered with pits is made a maximum as shown in FIG. 6C (A), and the pit arrays C provide a unit in which the area covered with pits is made a minimum as shown in FIG. 6C (B). Such dots are arranged at required positions to form letters. The letters, e.g. "SEGA" in FIG. 6A are formed in the trademark indication region 15 defined over substantially 1000 tracks. In FIGs. 6A to 6C, an indication in the predetermined region 15 of the disc substrate 31 is formed as letters visible (readable or recognizable) from the underside surface 34 which is the optical detecting surface (see FIG. 5), but may be formed to be visible from the upper surface 38 opposite to the optical detecting surface (see FIG. 5). In FIG. 5, it is possible that the protection layer 37 may be formed of a transparent material so that a specific indication can be visible from the outer surface 38. As shown in FIG. 2, the game machine 10 includes a reading unit 17. The unit 17 is connected to the optical pickup 16 through the input/output interface 24b. As shown in FIG. 7, the unit 17 includes an information detecting unit 18 and a comparison unit 19. The information detecting unit 18 includes a random number generating circuit 20 which functions as a selection unit. The information detecting unit 18 controls reading positions of the optical pickup 16 with respect to the CD-ROM 12 and generates outputs of detection signals (a) commanding the optical pickup to read specific tracks which are located in the trademark indication region 15 and are to be compared. The specific tracks are selected at random from a plurality of tracks which are composed of pit arrays forming comparison data A. The selection is determined by a random number generated by the random number generating circuit 20. That is, the optical pickup 16 selects and reads information from specific pit arrays selected from pit arrays which indicate a plurality of unit information. The pit array information (b) read from the specific tracks is supplied to the comparison unit 19. Specific tracks to be read by the optical pickup 16 can be obtained by selecting several units, wherein one track is defined as a unit or wherein a plurality of tracks are defined as a unit. The comparison unit 19 stores base data D (see FIG. 8) as digital signals in a semiconductor ROM. The base data D is reference information or standard information for judging agreement of data A therewith. The base data D corresponds to a reference indication such as the specific indication "SEGA" as shown in FIG. 8. The digital reference data corresponding to the specific indication "SEGA" is stored in a semiconductor ROM in which a reference unit is a set of data corresponding to each track consisting of a set of pits. The specific indication A is formed on the CD-ROM disc as the same group of pits as the reference indication D. The specific indication A to be compared is detected at the selected tracks, a comparison unit being a respective track consisting of a set of pits. When the comparison has found that the data A to be compared and the reference data D agree with each other, it is judged that the specific indication is displayed in the region; and when the comparison has found that the data A to be compared and the reference data D disagree with each other, it is judged that the specific indication is not displayed in the predetermined region. The comparison unit 19 generates comparison result information (c) as an output. That is, the comparison unit 19 functions as storage for storing base or reference data corresponding to the specific indication D; as an output unit for comparing data to be compared, which are indicative of pit array information of a specific indication A, with the reference data and generating an output based on the comparison result; and as a judging unit for judging whether or not the specific indication is displayed. The operation of the read unit 17 will be explained with reference to the flow chart of FIG. 9. The game machine 10 is powered on to start the checking operation. First the information detecting unit 18 determines specific tracks to be compared (Step S1). The specific tracks to be compared for the data A are determined as, for example, Track 1, Track 2, etc. corresponding to random numbers generated by the random number generating circuit 20. Track numbers corresponding to a predetermined number of tracks are selected at random. Next a part of the data to be compared is read by the optical pickup 16 from the CD-ROM 12 which is a medium to be checked (Step 2). The optical pickup 16 is moved to a position corresponding to the specific tracks to read information from pit arrays of the specific tracks. Subsequently the read data and reference data are compared with each other (Step S3). The information read from the pit arrays and the reference data D are compared by the comparison unit 19. Then the comparison unit 19 judges whether or not the data agree with each other (Step S4). When the comparison unit 19 has found disagreement between the read out information and the reference information, the unit 19 judges NO and conducts error processing (Step S5) and the checking operation is over. On the other hand, when the read information and the reference information agree with each other, the unit 19 judges YES, and judges whether or not all the data determined in Step S1 have been compared (Step S6). The judgement is YES after comparison of all the data to be compared and then the comparison operation is over. If the judgement is NO, namely all the steps of comparison have not been finished, then the procedure is returned to Step S2 to read data to be compared. This operation is repeated until all of the information to be checked has been compared and judged. When the data agree with each other, the information detecting unit 18 reads program information in the program region 14. When the data disagree with each other, the information detecting unit 18 does not read the program information in the program region 14 or stops the game. In the above-described checking operation, track numbers to be checked are selected for each checking operation and concurrently with selection of track numbers the number of tracks to be checked or the amount of data to be checked for each checking operation may be varied. Thus the reading unit 17 selects at random specific tracks to be compared without checking all the tracks, whereby the checking can be conducted in a short period of time. Furthermore, such shortened time of the checking allows larger data of larger numbers of tracks or larger images to be set as data A to be compared, which improves security. Since the tracks to be checked are changed at the start of every checking operation, data A to be compared stored in the CD-ROM 12 as a medium to be checked must be complete data, i.e. a complete image. In addition, a more accurate check is enabled by varying the number of specified tracks for every checking operation. A counterfeiter, who wants to fabricate a CD-ROM acceptable in an electronic device or information processing device of an authentic game machine or others, is required to indicate at the predetermined position of the CD-ROM a designated specific indication as data A to be compared corresponding to base data D as reference information stored in the authentic electronic device or information processing device. If he does, he will be accused as an illegal infringer of a proprietary right. The designated specific indication is exemplified by a trademark, a logotype or a tradename protected by trademark law, or a design, a mark, an image, etc. protected by design law. Designs, marks, images, etc. are protected in some states by design and patent law, copyright law, etc. The reference data D is subjected to information compression processing to reduce the amount of data, whereby the read unit 17 occupies a smaller area and reduces costs. In the above-described embodiment the region for a specific indication on a CD-ROM to be security checked is not limited to the position shown in FIG. 3 and can be varied. As exemplified in FIG. 10A, a zone 15a in which game program information is not written is defined inside the program region 14 or an information recording zone, along an inner circumference of the disc, and the region 15 for indicating a specific indication with a set of pits may be formed in the zone 15a. As exemplified in FIG. 10B, a zone 15b in which game program information is not written is defined outside the program region 14 or an information recording zone, along an outer circumference of the disc, and the region 15 for indicating a specific indication with a set of pits may be formed in the zone 15b. That is, these zones 15a, 15b are defined as indication forming zones on parts other than the information recording zone, and the region 15 is defined as an indication region in the zone 15a or 15b. In the variation of FIG. 10C, a plural number of regions 15 may be formed continuously or at a certain interval in the zone 15b. The same specific indication may be indicated in the respective regions 15, or two different indications may be indicated alternately in the respective regions 15. In this variation, certain of the regions 15 may be selected at random as data A to be compared for the checking out of the plural regions 15, based on random numbers generated by the random number generating circuit 20. Combination of the regions 15 at positions selected at random, and tracks in the selected regions selected at random can enhance security. As exemplified in FIG. 10D, the zone 15b may be provided outside the read-out region 14b of the CD-ROM 12, so that the zone 15b can be clearly separated from the program region 14 storing information, whereby controls for reading the information and for detecting the specific indication can be facilitated. In the zone 15b, as exemplified in FIG. 10D, the images TRADE MARK "SEGA" and PRODUCED BY OR UNDER LICENSE FROM SEGA ENTERPRISES, LTD. are formed with a set of pits. As a specific indication for the above-described security check, in addition to various letters, patterns, etc., registered trademarks, registered designs, designs such as characters etc. protected by copyrights, trade names, indication marks used by industrial groups, etc. may be used as long as they are identifiable and effectively exclusive. That is, it is preferred that a reference indication is able to hinder an unauthorized person from indicating the same. The reference indication may be owned, or its use may be granted by a license agreement. A plural number of the same indication may be used, or a combination of a plural number of different indications may be used. Furthermore, an indication formed in the region 15 of the CD-ROM 12 is formed in a visible size and shape, and may be formed in a sector along a peripheral edge of the CD-ROM 12. The present invention is applicable to security systems for electronic devices for reading information for use from information storage media storing game programs, musical software, dictionaries, computer programs, etc. It is especially applicable to security systems for information processing devices for optically reading program information stored in CD-ROMs to play games.

Claims: An electronic device (10) comprising a medium mounting unit (11) on which an information storage medium (12) is to be detachably mounted, and authenticity checking means for checking authenticity of the information storage medium (12); CHARACTERIZED IN THAT: the information storage medium (12) comprises an information region (14), and an indication region (15) on which a visual indication (A) is formed so that the visual indication has a property of being visually recognizable by the human naked eye as well as a property of allowing the electronic device (10) to read data necessary for the authenticity check when the electronic device (10) detects a selected partial area of the indication region (15); and the authenticity checking means of the electronic device has a storage means which stores reference data (D) indicative of the visual indication (A), selection means (20) for selecting a partial area of the indication region (15), the selected partial area being less than the whole area of the indication region (15), detection means (18) for detecting the selected partial area to output data indicative of part of the visual indication (A), and comparison means (19) for comparing the detected data with the reference data (D) to check the authenticity of the storage medium (12). An electronic device (10) according to claim 1, wherein the information storage medium is an information storage disc (12); wherein the indication region (15) is defined over a plurality of tracks of the information storage disc (12); and wherein the partial area of the indication region (15) selected by the selection means (20) is at least one track selected from the plurality of tracks. The electronic device of claim 1 or claim 2, characterized in that the information region (14) stores information with optically detectable pits and the visual indication (A) of the indication region (15) is formed with an aggregation of optically detectable pits; and in that the detection means (18) of the electronic device (10) optically reads both the information in the information region (14) and the visual indication (A) in the indication region (15). The electronic device of any one of claims 1 to 3, characterized in that the selection means (20) selects at random the selected partial area of the indication region (15). An electronic device (10) comprising a disc mounting means (11) on which an information storage disc (12) is to be mounted, and authenticity checking means for checking authenticity of the disc (12); CHARACTERIZED IN THAT: the disc (12) comprises an information storing zone (14) with information recorded with pits, and an indication forming zone (15) defined in an area different from the information storing zone (14), the indication forming zone (15) including a plurality of indication regions defined in the indication forming zone (15), each of said plurality of indication regions being formed with a visual indication (A) so that the visual indication (A) has a property of being visually recognizable by the human naked eye as well as a property of allowing the electronic device to read data necessary for the authenticity check; and the authenticity checking means of the electronic device has a storage means which stores reference data (D) indicative of the visual indication (A), selection means (20) for selecting a region at random from said plurality of indication regions, detection means (18) for detecting the selected region to output data indicative of the visual indication (A), and comparison means (19) for comparing the detected data with the reference data (D) to check the authenticity of the disc (12). The electronic device of claim 5, characterized in that the indication forming zone (15) is defined over a plurality of tracks, the selection means (20) includes means for selecting at random at least one out of the plurality of tracks, and the detection means (18) detects the selected region on the selected track to output data indicative of part of the visual indication (A) corresponding to the selected track. The electronic device of any one of the preceding claims, characterized in that the information storage medium or the information storing disc (12) is a CD-ROM, and the detection means optically detects the indication region (A). The electronic device of any one of the preceding claims, characterized by further comprising reading means (18) for reading the information in the information region or information storage zone (14) in response to an output from the comparison means (19) when the detected data agrees with the reference data (D). The electronic device of any one of the preceding claims, characterized by further comprising control means operable in response to an output from the comparison means (19). The electronic device of any one of the preceding claims, characterized in that the information stored in the information region or information storing zone (14) is a game program and data. The electronic device of any one of the preceding claims, characterized in that the use of the visual indication (A) is legally prohibited to a person other than those authorized. The electronic device of any one of the preceding claims, characterized in that the visual indication (A) is a trademark, a tradename, a logotype, a mark, a pattern, a letter, a character or a message. The electronic device of any one of the preceding claims, characterized in that the visual indication (A) is a trademark "SEGA". The electronic device of any one of the preceding claims, characterized in that the visual indication (A) is a trademark "SEGA" substantially as shown in FIGs. 4 and 6A.

Inventors: OWAKI HIDETAKA, OWAKI, HIDETAKA
Applicants: SEGA ENTERPRISES KK, SEGA ENTERPRISES, LTD.
Application year: 1994
Main classification: G11B20
IPC codes: G11B19, G11B23, G11B7, G11B20